A general solution for Stokes flow and its application to the problem of a rigid plate translating in a fluid

A general solution for 3D Stokes flow is given which is different from, and more compact than the exist ing ones and more compact than them in that it involves only two scalar harmonic functions. The general solution deduced is combined with the potential theory method to study the Stokes flow induced by a rigid plate of arbitrary shape trans lating along the direction normal to it in an unbounded fluid. The boundary integral equation governing this problem is derived. When the plate is elliptic, exact analytical results are obtained not only for the drag force but also for the ve locity distributions. These results include and complete the ones available for a circular plate. Numerical examples are provided to illustrate the main results for circular and ellip tic plates. In particular, the elliptic eccentricity of a plate is shown to exhibit significant influences.

Modeling method and preliminary model of Asteroid Toutatis from Chang'E-2 optical images

Shape modeling is fundamental to the analysis of dynamic environment and motion around asteroid. Chang＇E- 2 successfully made a flyby of Asteroid 4179 Toutatis and obtained plenty of high-resolution images during the mis- sion. In this paper, the modeling method and preliminary model of Asteroid Toutatis are discussed. First, the optical images obtained by Chang＇E-2 are analyzed. Terrain and silhouette features in images are described. Then, the modeling method based on previous radar model and preliminary information from optical images is proposed. A preliminary polyhedron model of Asteroid Toutatis is established. Finally, the spherical harmonic coefficients of Asteroid Toutatis based on the polyhedron model are obtained. Some parameters of model are analyzed and compared. Although the model proposed in this paper is only a preliminary model, this work offers a valuable reference for future high-resolution models.

High-flow nasal cannula oxygen therapy during anesthesia recovery for older orthopedic surgery patients: A prospective randomized controlled trial

BACKGROUND Hypoxemia is a common complication in older patients during postoperative recovery and can cause pulmonary complications.Therefore,reducing the incidence of postoperative hypoxemia is a clinical concern.AIM To investigate the clinical efficacy of high-flow nasal cannula oxygen(HFNCO)in the resuscitation period of older orthopedic patients.METHODS In this prospective randomized controlled trial,60 older patients who underwent orthopedic surgery under general anesthesia were randomly divided into two groups:those who used conventional face mask and those who used HFNCO.All patients were treated with 60%oxygen for 1 h after extubation.Patients in the conventional face mask group were treated with a combination of air(2 L)and oxygen(2 L)using a traditional mask,whereas those in the HFNCO group were treated with HFNCO at a constant temperature of 34℃ and flow rate of 40 L/min.We assessed the effectiveness of oxygen therapy by monitoring the patients’arterial blood gas,peripheral oxygen saturation,and postoperative complications.RESULTS The characteristics of the patients were comparable between the groups.One hour after extubation,patients in HFNCO group had a significantly higher arterial partial pressure of oxygen(paO_(2))than that of patients in conventional face mask group(P<0.001).At extubation and 1 h after extubation,patients in both groups showed a significantly higher arterial partial pressure of carbon dioxide(paCO_(2))than the baseline levels(P<0.001).There were no differences in the saturation of peripheral oxygen,paO_(2),and paCO_(2) between the groups before anesthesia and before extubation(P>0.05).There were statistically significant differences in paO_(2) between the two groups before anesthesia and 1 h after extubation and immediately after extubation and 1 h after extubation(P<0.001).However,there were no significant differences in the oxygen tolerance score before leaving the room,airway humidification,and pulmonary complications 3 d after surgery between the two groups(P>0.05).CONCLUSION HFNCO can improve oxygen partial pressure and respiratory function in elderly patients undergoing orthopedic surgery under general endotracheal anesthesia.Thus,HFNCO can be used to prevent postoperative hypoxemia.

Severe gastric insufflation and consequent atelectasis caused by gas leakage using AIR-Q laryngeal mask airway:A case report

BACKGROUND The airways of patients undergoing awake craniotomy(AC)are considered“predicted difficult airways”,inclined to be managed with supraglottic airway devices(SADs)to lower the risk of coughing or gagging.However,the special requirements of AC in the head and neck position may deteriorate SADs’seal performance,which increases the risks of ventilation failure,severe gastric insufflation,regurgitation,and aspiration.CASE SUMMARY A 41-year-old man scheduled for AC with the asleep–awake–asleep approach was anesthetized and ventilated with a size 3.5 AIR-Q intubating laryngeal mask airway(LMA).Air leak was noticed with adequate ventilation after head rotation for allowing scalp blockage.Twenty-five minutes later,the LMA was replaced by an endotracheal tube because of a change in the surgical plan.After surgery,the patient consistently showed low tidal volume and was diagnosed with gastric insufflation and atelectasis using computed tomography.CONCLUSION This case highlights head rotation may cause gas leakage,severe gastric insufflation,and consequent atelectasis during ventilation with an AIR-Q intubating laryngeal airway.

Construction of Aniline Trimer Based Conjugated Polymers through Schiff Base Reaction and Their Use as Feedstock for Infrared Stealth Coatings

In order to meet the demand for infrared stealth materials in the military field,conjugated polymers containing Schiff base moieties were designed and prepared.Various dialdehyde monomers were introduced and their effect on the comprehensive properties were systematically characterized.The resulted polymers could be cast in solution to prepare polymer coatings.The coatings exhibited high thermal stability up to 400℃ at 5%weight loss,and excellent mechanical performance with high Young’s modulus and hardness.The infrared emissivity values varied from 0.587 to 0.627 at wavelength of 8-14μm and ranged from 0.595 to 0.609 at wavelength of 2-22μm.Specifically,it was found that the ATTPAL structure with carbazole moieties had a lower band gap and better electrical conductivity by photoelectric test and DFT theoretical analysis.Meanwhile,the infrared emissivity value of ATTPAL coating was the lowest compared with p-phenyl and pyridyl containing analogues,suggesting it was potential material for the future development of infrared stealth technology.The combined results showed that reducing the band gap and improving the electrical conductivity of the structure were both beneficial to the reduction of infrared emissivity.It would positively provide new ideas for the design of infrared stealth materials.

Intracranial hemangiopericytoma with right-sided aortic arch: a case report and summary of experience

Hemangiopericytoma is clinically rare and easily confused with meningioma.Right-sided aortic arch is also a rare disease of congenital cardiovascular variability.The intracranial hemangiopericytoma associated with the right-sided aortic arch has not been reported in the literature.We are here to register a case of right aortic arch concurrent with intracranial hemangiopericytoma;the patient was initially thought to be a simple meningioma,but he was eventually diagnosed as a hemangiopericytoma with right aortic arch and multiple intracranial vascular stenosis and malformation.Whether there was a genetic correlation between the two provides a potential research direction for us.Therefore,the diagnosis and treatment of some rare diseases should be a more comprehensive analysis and evaluation.Adequate examination and accurate diagnosis are crucial,which will directly affect the efficacy of surgery and the prognosis of patients.

Sequencing and analysis of the complete mitochondrial genome in Anopheles sinensis(Diptera:Culicidae)

Background:Anopheles sinensis(Diptera:Culicidae)is a primary vector of Plasmodium vivax and Brugia malayi in most regions of China.In addition,its phylogenetic relationship with the cryptic species of the Hyrcanus Group is complex and remains unresolved.Mitochondrial genome sequences are widely used as molecular markers for phylogenetic studies of mosquito species complexes,of which mitochondrial genome data of An.sinensis is not available.Methods:An.sinensis samples was collected from Shandong,China,and identified by molecular marker.Genomic DNA was extracted,followed by the Illumina sequencing.Two complete mitochondrial genomes were assembled and annotated using the mitochondrial genome of An.gambiae as reference.The mitochondrial genomes sequences of the 28 known Anopheles species were aligned and reconstructed phylogenetic tree by Maximum Likelihood(ML)method.Findings:The length of complete mitochondrial genomes of An.sinensis was 15,076 bp and 15,138 bp,consisting of 13 protein-coding genes,22 transfer RNA(tRNA)genes,2 ribosomal RNA(rRNA)genes,and an AT-rich control region.As in other insects,most mitochondrial genes are encoded on the J strand,except for ND5,ND4,ND4L,ND1,two rRNA and eight tRNA genes,which are encoded on the N strand.The bootstrap value was set as 1000 in ML analyses.The topologies restored phylogenetic affinity within subfamily Anophelinae.The ML tree showed four major clades,corresponding to the subgenera Cellia,Anopheles,Nyssorhynchus and Kerteszia of the genus Anopheles.Conclusions:The complete mitochondrial genomes of An.sinensis were obtained.The number,order and transcription direction of An.sinensis mitochondrial genes were the same as in other species of family Culicidae.

Phylogeny of certain members of Hyrcanus group(Diptera:Culicidae)in China based on mitochondrial genome fragments

Background:Species of the A nopheles hyrcanus group are widely distributed in Palearctic and Oriental regions and some of them are important malaria vectors.The cryptic species of An.hyrcanus group was almost impossible to identify based only on their morphology.The phylogenetic relationship of An.hyrcanus group was also not clear.Methods:Five members of An.hyrcanus group were identified by rDNA ITS2 sequencing as An.yatsushiroensis,An.belenrae,An.kleini,An.lesteri and An.sineroides.The mitochondrial genome fragments were sequenced and annotated using the mitochondrial genome of An.sinensis as reference.Based on the four segments and Joint Data sequences of these species,and other four anopheline species downloaded from GenBank,intraspecific as well as interspecific genetic distances were calculated and the phylogenetic trees were reconstructed by the methods of neighbor joining,maximum parsimony,minimum evolution and maximum likelihood.Findings:Four parts of mitochondrial genomes,which were partial fragments COI+tRNA+COII(F5),ATP6+CO///(F7+F8),A/D7(F19)and IrRNA(F21),were obtained.All fragments were connected as one sequence(referred as Joint Data),which had a total length of 3393 bp.All fragment sequences were highly conservative within species,with the maximum p distance(0.026)calculated by F19 of An.belenroe.The pairwise interspecific p distance calculated by each fragment showed minor or even no difference among An.sinensis,An.kleini and An.belenrae.However,interspecific p distances calculated by the Joint Data sequence ranged from 0.004 (An.belenrae vs An.kleini)to 0.089(An.sineroides vs An.minimus),and the p distances of the six members o f An.hyrcanus group were all less than 0.029.The phylogenetic tree showed two major clades:all subgenus A nopheles species(including six members of An.hyrcanus group,An.otroparvus and An.quadrim aculatus A)and subgenus Cellia(including An.dirus and An.minimus).The An.hyrcanus group was divided into two clusters as{(An.lesteri,An.sineroides)An.yatsushiroensis)and({An.belenrae,An.sinensis)An.kleini)).Conclusions:The An.hyrcanus group in this study could be divided into two clusters,in one of which An.belenrae,An.sinensis and An.kleini were most closely related.More molecular markers would make greater contribution to phylogenetic analysis.

Analysis of nicotine-induced metabolic changes in Blakeslea trispora by GC-MS

Blakeslea trispora is a natural source of carotenoids,includingβ-carotene and lycopene,which have industrial applications.Therefore,classical selective breeding techniques have been applied to generate strains with increased productivity,and microencapsulatedβ-carotene preparation has been used in food industry(Li et al.,2019).In B.trispora,lycopene is synthesized via the mevalonate pathway(Venkateshwaran et al.,2015).Lycopene cyclase,which is one of the key enzymes in this pathway,is a bifunctional enzyme that can catalyze the cyclization of lycopene to produceβ-carotene and exhibit phytoene synthase activity(He et al.,2017).

有机硅改性聚氨酯/纳米SiO_(2)复合超疏水涂层的制备

以4,4’-二苯基甲烷二异氰酸酯(MDI)、聚四氢呋喃醚二醇(PTMEG)、羟基封端的聚二甲基硅氧烷(HO-PDMS)、1,4-丁二醇(BDO)为原料,合成了有机硅改性的聚氨酯溶液,通过核磁共振、红外光谱技术对其结构进行表征,并研究了羟基硅油加入量对聚氨酯热稳定性、疏水性的影响.以有机硅改性的聚氨酯溶液为基体、含氟硅烷偶联剂改性的纳米二氧化硅颗粒为填料,喷涂制备超疏水涂层,研究了填料添加量对复合涂层疏水性的影响.结果表明:当硅油加入量为9 wt%,填料加入量为60 wt%时,复合涂层性能最优,水接触角为153.3°,滞后角为6.3°.经过200℃加热1 h后,仍然具有大于150°的水接触角.对复合涂层进行磨损实验与防冰测试,结果表明:该复合涂层在磨损过程中,在基底暴露之前,整个涂层基体都具有超疏水性;并且该涂层能有效降低结冰温度,延长结冰时间,具有良好的防冰性能.

Microencapsulated β-carotene preparation using different drying treatments

β-Carotene is one of the most abundant natural pigments in foods;however,usage of β-carotene is limited because of its instability.Microencapsulation techniques are usually applied to protect microencapsulated p-carotene from oxidization.In this study,β-carotene was microencapsulated using different drying processes:spray-drying,spray freeze-dryi ng,coati ng,and spray granulation.The properties of morphology,particle size,water con tent,thermal characteristic,and chemical stability have been explored and compared.Scanning electron microscopy measure?ments showed that the coated powder had a dense surface surro un ded by starch and suggested that the coati ng process gave a microencapsulated powder with the smallest bulk density and the best compressibility among the prepared powders.The chemical stabilities of microcapsules were evaluated during six months of storage at different temperatures.The coated powder had the highest mass fraction of β-carotene,which indicated that the coating process was superior to the three other drying processes.

Thiocarbonylation of C(sp^(3))-H bonds in pyridylamines with CS;: Facile synthesis of pyrido[1,2-a]pyrimidine-4-thiones

Herein, a facile synthesis of valuable pyrido[1,2-a]pyrimidine-4-thiones is reported via novel thiocarbonylation of C(sp^(3))-H bonds with carbon disulfide(CS_(2)). This reaction features easy availability of substrates,good functional group tolerance, high yields, facile scalability and atom economy. Mechanistic investigations indicate that sulfate anion and sulfuric anhydride anion might be involved in this reaction.